Mercedes-Benz is fighting a US lawsuit claiming its diesel engines shut down emissions cleaning systems in low temperatures. And Volkswagen remains mired in the aftermath of its emissions cheating diesel scandal.

But Mercedes-Benz remains committed to a diesel-powered future.

The German company was hit with a class action lawsuit in February this year, alleging the company has programmed its emissions cleansing systems to stop working in low temperature conditions thus making them dirtier than the company claimed.

But the company has denied this, telling Drive it will fight the case saying the lawsuit is "unfounded".

But the lawsuit comes as the company prepares to launch its new generation diesel engine - an all-new, all-aluminium 2.0-litre four-cylinder turbo diesel that is 13 per cent more efficient and 17 per cent lighter.

Asked if the lawsuit will affect Mercedes' image and the reputation surrounding diesel, Wilko Stark, director of product planning for Mercedes-Benz cars, admitted it was hard to predict.

Mercedes-Benz still believes in diesel despite a US lawsuit and the VW emission scandal. Photo: Supplied

"This is a big, big question," Stark said. "I think the question is 'does it have any negative impact on the mix of diesel engines in total?' This is a question still to be answered."

But he explained Mercedes is prepared if demand for diesel cars drops thanks to its newly developed modular family of engines.

"We still have the big, big benefit regarding our new production systems and our new engines that our new diesel engines and new petrol engines, four-cylinder and six-cylinder, have more or less the same concept," he said. "So we share more or less the same parts and therefore we can mix, we can have different mixes and react to the market. If the mix is going down we switch to petrol, if the mix is going up we switch to diesel. We do have the flexibility in the future with our production system."

But regardless of the current situation Stark is adamant Mercedes would have developed the all-new diesel engine anyway in order to meet ever stricter emissions standards in Europe.

"For one simple reason," he said, "because the discussion that is going on now with the public has nothing to do with this new diesel engine. Because this new diesel engine meets all requirements, all legislation coming in '18 to '19 to '20, so you really have to separate this discussion. We still believe in diesel technology, it has a big benefit regarding carbon dioxide and also it is a big, big lever for the overall fuel consumption targets. So the clear answer is yes.